The present invention relates to data transfer and specifically a method to direct the PDP context of a data packet in a mobile station containing one or several applications that perform packet format data transfer. The present invention also targets a mobile station realising the method.
A WCDMA (Wideband Code Division Multiple Access) air interface being defined and the new radio network services it has generated along with the evolution of GSM/GPRS (Global System for Mobile Telecommunications/ General Packet Radio System) based trunk line give a starting point to a third generation evolved packet format data transfer. The architecture of a new packet switched data transfer recognises the division between circuit and packet switched data transfer present in conjunction with GSM/GPRS and, being identical to GPRS core network in many parts, enables co-operation between second and third generation packet switched data transfer.
Even though the available bandwidth in new third generation systems will be larger that earlier, the radio interface will continue to be the bottleneck of the system. New packet switched data transfer networks have to support many uses requiring many different levels of resources, e.g. real time video conferencing services on one hand and background file transfer on the other hand. To improve the use of limited resources solutions must be developed to control the use of a radio resource according to the needs of the current use.
With the increase in packet format data transfer the border between traditional telecommunication and data communication along with the border between applications used with a wireless connection and a wired network is being blurred. In order to guarantee a user base as large as possible it is very desirable that applications be independent of the selected environment. Since new services are, at least for now, being created more on the wired network side, an as good as possible adaptability of these applications to especially wireless connections is an important design principle.
In the UMTS (Universal Mobile Telecommunications System) system being defined, which system is based on the third generation WCDMA radio interface, the initiation of a connection essentially contains the activation of a PDP (Packet Data Protocol, PDP) context. A PDP context is equivalent to allocating of a PDP address and initiating a logical contact conforming to a certain quality of service through an UMTS network. The quality of service (QoS) is defined by a group of QoS parameters defining the quality of service, which parameters include e.g. delay, BER (Bit Error Rate), maximum bit rate and order of service. Thus the requested and negotiated QoS parameters of one PDP context form one QoS profile.
Already in second generation GPRS system it has been possible to define a different PDP context to each application according to the PDP address. For this functionality a reference is made to the Finnish patent application F1990009, applied by Nokia Telecommunications. Since the application is still classified, the subject is presented in essential parts also in this application. For example, the defined PDP addresses can pertain to e-mail applications, where response times are not a critical factor and correspondingly the interactive applications linked to other PDP addresses do not tolerate delay and thus demand quick pass through times. To realise these differences also in more evolved packet radio networks, a suggestion has been made to describe the packets of each application into a suitable PDP context using filters. A filter is preferably a piece of information transmitted between the edge elements of a packet radio network in conjunction with the modification or activation of a PDP context, which information consists of a group of pre-defined parameters or conditions, with the aid of which said edge element can recognise data packets pertaining to a certain application and thus describe said packets directly into the desired PDP context. In uplink data transfer the description is realised in the terminal of the user and in downlink data transfer the description is realised in a gateway GPRS support node GGSN. However, in IP (Internet Protocol) connections this means that an application attached to a certain PDP address can use only one QoS profile. As services continue to grow more versatile combinations of sound, image and data this is an awkward limitation, which hopefully will be eliminated in conjunction with UMTS evolution.
In a GPRS connection, then, a minimum filter can be a PDP address. In UMTS environment and possibly in future GPRS versions the filter must, in order to support several PDP contexts, typically contain information on at least the TCP/UDP (Transport Control Protocol/User Datagram Protocol) ports, source IP address and target IP address. The information on TCP/UDP ports is located in TCP/UDP headers which is contained in the data part of an IP packet. On the user""s terminal the classification to different PDP contexts is typically and preferably done under the IP layer, which means that receiving the data needed for classification requires, in addition to a layer breach, extra processing in the terminal, as the IP packet must be deconstructed in order to find out the filter data needed. In wireless terminals the performance of the processor is limited, so an increase in the steps taken to process packets is very undesirable; the classification of data packets in the terminal should indeed be realised as effectively as possible and in a manner as easy as possible. Additionally, when using the IPSEC (IP Security) function, the data inside an IP data unit and thus also the information about TCP/UDP ports in the TCP header is encrypted. In this case classification of the data packets in the terminal becomes more difficult, since even packets belonging to different applications cannot be distinguished by a mere IP address.
Now a method and means realising the method have been invented to solve the problems presented above in order to direct uplink data packets into the desired PDP contexts are solved or at least their effect is essentially decreased. The invention describes a method to direct the PDP context of a data packet in a mobile station containing one or several applications realising packet format data transfer, in which method a data packet is received from an application, which packet contains a first identifier to identify the application that has produced the data packet. The method is characterised in that input piece of information attached to said application is received, which piece of information contains information about one or several separate data flows; a PDP context is defined to each of the data flows of the application on basis of said piece of information; a second identifier identifying the data flow is added to the data packet; and the departing data packet is classified into a PDP context on basis of said first and second identifier.
The present invention also targets a mobile station according to claim 10. Preferable embodiments have been presented in dependent claims.
The gist of the invention is that a control device is added to the terminal, which control device receives input at least at the start of an application, on the basis of which input it defines and realises the PDP context(s) to each data flow of the application. Preferably said control device describes the PDP context of each data flow to a detector in the header of the IP layer, with the aid of which detector the PDP context to be used in the transfer of the data packet can easily and quickly be defined also in a mobile station of limited performance.
In addition to simplifying the classification process the present invention yields other advantages. The control device preferably has several interfaces to different sources of input, which means that possibilities to make definitions are increased and the data to support definitions still has to be updated only to the control unit. With the aid of the control device a mobile station can be adapted to support applications or even application interfaces, which are not necessarily adapted to packet radio network use.